Preheat your oven to 375°F (190°C) and coat a 9x13-inch baking dish with nonstick spray.

Bring salted water to a boil in a large pot, add cavatappi pasta, and cook for 7-8 minutes until al dente. Drain and rinse under cold water.

In a mixing bowl, combine cream of chicken soup, half & half, and Dijon mustard. Whisk until smooth and season with parsley, seasoned salt, and black pepper.

Add shredded Swiss cheese and diced rotisserie chicken to the sauce mixture. Fold in the drained cavatappi, ensuring it's well coated.

Combine melted butter with panko breadcrumbs and grated Parmesan cheese in a small bowl. Stir until breadcrumbs are coated.

Pour the pasta and chicken mixture into the baking dish and spread evenly. Sprinkle the buttery panko topping over the surface.

Bake for 25-30 minutes until bubbling and golden brown. Watch closely to avoid over-browning.

Let the casserole rest for a few minutes after baking. Garnish with fresh parsley before serving.